Method for making precoiled helical fins



Sept- 20; 1949- E. BRUEGGER 2,482,241

METHOD FOR MAKING PRECOILED HELICAL FINS original Filed Sept. 8, 1944 5 Shets-Sheet 1 I N VEN TOR.

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Sept; 20, 1949. E. BRUEGGER HEI'I'HQD FOR MAKING PRECOILED HELICAL FINS Original Filed Sept. 8, 1944 5 Sheets-Sheet 2 INVENTOR. ERA/E6 7' Sr/#05665? 73w MFMJ; v- M H15 ATTORNEYS 3&

atrm'm HUUM Sept. 20, 1949.. E. BRUEGGER METHOD FOR MAKING PRECOILED HELICAL PINS ori inal Filed Sept. 8, 1944 5 Sheets-Sheet 3 m w m 5%.. 7 4 4 wy 7+ 3 y r 2 J BY I TM Hi5 ATTORNEYS tit/ARC POO Sept. 20, 1949.

E. BRUEGGER METHOD FOR MAKING PRECOILED HELICAL FINS Original Filed Sept. 8, 1944 5 Sheets-Sheet 4 INVENTOR. EPA/EJ7 B/PUEGGf/E H15 ATTORNEYS SUM-(F POOH Sept. 20, 1949.

5. BRUEGGER METHOD FOR MAKING PRECOILED HELICAL PINS 5 Sheets-Sheet 5 Original Filed Sept. 8, 1944 INVEN TOR. EF/VFS T BFUfGGf F 1776 ATTORNEYS Patented Sept. 20, 1949 METHOD FOR MAKING PRECOILED HELICAL FINS Ernest Bruegger, Massillon, Ohio, assignor to The Griscom-Russell Company, New York, N. Y., a corporation of Delaware Original application September 8, 1944, Serial No.

553,153, now Patent No. 2,437,500, dated March Divided and this application March 15, 1947, Serial No. 734,960

3 Claims. (Cl. 153-3) This invention relates to the manufacture of fins and more particularly concerns an improved method of making helical fins useful in the manufacture of cylindrical elements from or to which heat is transferred, such as cylinders for internal combustion engines. This application is a division of my co-pending application Serial No. 553,153, filed September 8, 1944 (Patent No. 2,437,500, granted March 9, 1948).

Many devices and processes require the rapid transmission of considerable quantities of heat from or to a tubular or cylindrical body. For example, cylinders of internal combustion engines employed in aircraft must be cooled to prevent failure of these or other parts of the engine in operation. The power output of such engines for a given piston displacement has recently been greatly increased by the use of high compression ratios and new fuels, and this increase necessitates an increase in the heat radiating capacity of the cylinders to prevent overheating.

Heat radiating fins for air-cooled engine cylinders have been produced by casting or machining them directly on and integral with the cylinder wall or a sleeve attached to the cylinder. These procedures are expensive, provide but a limited increase in the heat dissipating surface and in general produce cylinders which cannot be safely operated at power outputs obtainable from engines employing liquid cooled cylinders of the same piston displacement.

With the above and other considerations in mind, it is proposed in accordance with the present invention to provide an improved method which produces helically coiled fins for engine cylinders or like cylindrical components, whereby cylinders with greatly extended heat radiating surfaces may be produced. Another object of the invention is to provide a method which produces pre-coiled fin structures rapidly and inexpensively without wasting metal.

The fin preferably produced by my improved method is an edgewise wound helical ribbon having a substantially L-shaped foot along its inner edge. The bottom of this foot engages the cylindrical surface to which the fin is secured, and the end of the foot engages the face of an adjacent turn of the fin and thereby provides the proper spacing between the fin turns. I have found that attempts to bend the L-shaped foot along the inner edge of the fin to final form while bending a straight metallic ribbon into a helical coil result in buckling or other improper with such procedure it is diflicult to control the width and thickness of the foot element. I have devised a method in which a straight metallic ribbon is first bent edgewise into a helical coil while its inner edge portion is displaced at an angle of less than 90 to the remainder of the fin, and in which the pre-coiled fin thus produced is then continuously bent along its inner edge to finish the foot bend so as to dispose the foot normal to the radially extending fin.

The disclosed apparatus by means of which my method may be carried out is claimed in my copending application Serial No. 553,153 above referred to and in my co-pending application Serial No. 734,961, filed March 15, 1947 (Patent No. 2,469,223, granted May 3, 1949).

In describing the invention in detail, reference will be made to the accompanying drawings in which a typical embodiment of my improved apparatus suitable for carrying out my improved method has been illustrated. In the drawings:

Fig. 1 is an elevation partly in section, of a ribbon coiling machine embodying the invention;

Fig. 1A is a sectional view taken on the line IAIA of Fig. 2 showing the means for adjusting the angular position of the sleeve 35:

Fig. 2 is a plan view of the machine illustrated inFig. 1;

Fig. 3 is a sectional view taken along the line 33 of Fig. 2 and viewed in the direction of the arrows;

Fig. 4 is a sectional view taken along the line 44 of Fig. 3 and viewed in the-direction of the arrows;

Fig. 5 is a front end elevation of the machine;

Fig. 6 is a sectional view, on an enlarged scale, taken along the line 66 of Fig. 5 and showing the details of the ribbon bending mechanism;

Fig. 7 is a side elevation of a beading machine embodying the invention taken from the side from which a precoiled ribbon approaches the machine;

Fig. 8 is an elevation taken from the opposite side showing the machine illustrated in Fig. 7;

Fig. 9 is a plan view of the beading machine together with means for guiding a pre-coiled ribbon toward and away from the machine; and

Fig. 10 is a sectional view on an enlarged scale taken along the line Ill-l0 of Fig. '7, showing the bead forming rollers of the beading machine.

In general, my pre-coiling machine employs a pair of cooperating discs of different diameter having marginal end faces so disposed as to pinch or grip a straight metallic ribbon therebetween or irregular bending of the fin metal, and that and bend it continuously about a circular surface into a continuous edgewise wound helical coil. The gripping or pinching action of the disc end faces is obtained by disposing the discs with their axes adjacent but at a small angle to each other so thatthe ribbon gripping faces are close to each other and in peripheral alignment at and near the point where the gripping of the ribbon takes place, and are spaced more widely apart andradiallydisplaced at other points in their rotation. In order that the coiled ribbon may progress outwardly from the bending machine, the circular surface about which it is bent is disposed eccentrically with respect to the discs and preferably comprises a ring running on a shoulder of one of the discs and having an outer circular edge which forms the surface about which the ribbon is bent. This outer edge of the ring is disposed radially inward from the edge of the forming discs at the point where their faces grip the ribbon, but is substantially aligned with the outer periphery of the smaller of these discs at a diametrically opposite point. With this arrangement, the coiled ribbon is bent about the circular surface between the discs and moves outward axially of the discs over the peripheries of the smaller disc in a continuous coil.

Referring to Figs. 1 through 6, the disclosed embod-ment of my improved pre-coiling machine includes a stationary base carrying a swivel plate l2. The plate I2 is pivotally connected to the base II by a pin |4 threadedly secured to the base and extending through a boss in the swivel plate |2. The plate I2 is releasably clamped to the base H by a plurality of bolts I5 passing through slots I6 in the plate I2 and threadedly engaging the base When the bolts l5 are loosened, the swivel plate |2 may be moved in a horizontal plane about the pin H by an adjustLng screw IT. The screw I! is rotatably car ried in a bracket |8 fixed to the plate I2 and is held against movement through this bracket by a collar 47. The adjusting screw threadedly engages a post I9 which is fixed to the base II and passes through a slot 29 in the plate |2 (Figs. 1, 2 and 4) A bearing housing 2| is suitably fixed to the swivel plate l2 by brackets 22, a plate 23 and screws 24. As best shown in Fig. 1, a sleeve 25 is fixed within the housing 2| and carries anti-friction bearings 26 in which a shaft 2'! is journaled. The bearings 26 are preferably enclosed by end plates 28 provided with packing rings 32 to retain lubricant in the bearings.

The shaft 21 is driven by any suitable means. In the disclosed embodiment, this shaft is connected through a universal joint 3| to the output shaft of a speed reduction gearing unit 29 of known construction, and the input shaft of this unit is driven by a motor 39 through a belt 30'. Both the speed reduction gearing unit 29 and the motor 30 are fixed to the swivel plate I2.

The shaft 21 extends beyond the bearing housing 2| nto and through a rotary sleeve 33 which is journaled on anti-friction bearings 34 in a stationary cylindrical bracket 35. Th bracket 35 is secured to a plate 36 by supports 31. The plate 36 is so mounted as to be adjustably tiltable in a substantially vertical plane about the arcuate top of a key 38 fixed in a transverse groove in the base II, as shown in Figs. 1, 1A and 2. This adjust ment permits variation of the angular position of the axis of the rotary sleeve 33. The plate 36 is normally locked to the base I by the machine screws 39 which pass through enlarged openings 39' in the plate 36 as shown, and when these .4 screws are loosened the plate 36 may be tilted by a suitable adjustment of the set screws 49 which threadedly engage the plate 36 and bear on the base II on opposite sides of th key 38.

A ribbon forming disc 4|, having a central aperture through which the shaft 21 passes, is fixed to the front end of the rotary sleeve 33 (Figs. 1 and 6). This disc has an outwardly disposed marginal end face 42 having a beveled inner edge 43, as shown in Fig. 6. A second ribbon forming disc 44 is fixed to the end of the shaft 21 by a nut 45 or other suitable means. The disc 44 is of considerably smaller diameter than the disc 4| and has an inwardly disposed marginal end face 46. As shown in Fig. 6, the axes of rotation of the discs 4| and 44 lie close to each other but are disposed at a small angle to each other. The arrangement is such that the marginal end faces 42 and 46 of the respective discs lie parallel to and closel adjacent each other and in substantial peripheral alignment at and near one point in the rotation of the discs, and are more widely separate and displaced radially elsewhere. This point where the disc faces most closely approach each other Will be termed the pinch point herein. In the disclosed embodiment, the pinch point is slightly below a horizontal plane through the disc axes, and is substantially at the point where the line 6--6 of Fig. 5 crosses the disc faces to the left of the disc axes, as shown in that figure. The face 46 of the disc 44 is slightly conical so as to lie parallel to the face 42 of the disc 4| at the pinch point. The location of the pinch point and the spacing of the disc faces 42 and 46 may be variably adjusted by altering the angular positions of the axes of the discs 4| and 44. Swinging of the swivel plate I2 about the pin |4 alters the angular position of the axis of the outer disc 44, and tilting of the plate 36 about the arcuate key 38 alters the angular position of the axis of the inner disc 4|.

The outer disc 44 has a hub forming a shoulder 48. A pilot or bending ring 49 surrounds the shoulder 48, and the inner surface of this ring engages the shoulder adjacent the pinch point. The internal diameter of the pilot ring 49 is considerably larger than the diameter of the shoulder 48. The radial width of the ring 49 is such as to bring its outer edge 50 in substantial peripheral alignment with the beveled edge 43 of the inner disc face 42 at and near the pinch point. The outer edge 50 of the pilot ring 49 is preferably beveled as shown, to lie parallel to the beveled edge 43 of the inner ring face 42. These beveled surfaces may lie at an angle of approximately 45 to the disc faces 42 and 46. The ring 49 is of such size that its outer edge 50 is substantially flush with the periphery of the outer disc 44 at a point substantially diametrically opposite the pinch point, as shown in Figs. 5 and 6.

A stationary take-off finger 12 extends radially inward over the face 42 of the inner disc 4| to a point adjacent the outer edge 50 of the pilot ring 49. The finger 12 is fixed to a block 13 secured to a face plate 14 on the cylindrical bracket 35. The finger 12 is disposed adjacent but slightly beyond a point diametrically opposite the pinch point, as shown in Fig. 5, and serves to guide the first turn of the coiled ribbon 15 outward over the edge of the outer disc 44, thus giving the coiled ribbon a lead and causing it to progress axially outward from the forming discs.

The pilot ring 49 is held in frictionally movable engagement with the inner face of the disc 44 by a guide ring 52 of substantially the same radial dimensions as the ring 49, and a retaining plate 53 is fixed to the hub of the disc 44 by the screws 54 and holds the guide ring 52 and pilot ring 49 against the inner face of the disc 44 as shown in Fig. 6. With the arrangement described, the pilot ring 49 turns about an axis parallel to but spaced laterally from the axis of rotation of the disc 44. as illustrated in Figs. 5 and 6.

A driving connection is provided between the shaft 21 and the rotary sleeve 33 so that the discs 4| and 44 rotate in the same direction and at the same angular velocity. In the disclosed embodiment, a sprocket 55 is keyed to the shaft 21 adjacent the rotary sleeve 33, and the teeth 56 of this sprocket engage openings 51 in a collar 58 fixed to the sleeve 33 as shown in Figs. 1, 2 and 3. With this arrangement, the discs 4| and 44 are driven in unison from the shaft 21 despite the angle between the axes of the discs.

A pair of spaced guide discs 59 and 66 having a peripheral slot 6| therebetween are clamped together and carried by a shaft journaled in a bracket 62 fixed to the cylindrical bracket 35. The discs 59 and 60 are disposed with their peripheries close to those of the discs 4| and 44 at or closely adjacent the pinch point, with the slot 6| aligned with and forming a continuation of the space between the marginal end faces 42 and 46, as shown in Figs. 5 and 6.

A ribbon guide 63 having a vertically extending opening 64 of rectangular section therethrough is secured to a bracket 65 fixed to the cylindrical bracket 35 (Figs. 1 and 5). The opening 64 in the ribbon guide is disposed in alignment with the space defined by the disc faces 42 and 46 and the peripheral slot 6| between the guide discs 59 and 60. An oil trough 66 is supported at the upper end of the guide 63 around the opening 64 therethrough and a wick 61 disposed in this trough is supplied with lubricant from a reservoir 68 through a valved duct 69. The metallic ribbon 5| to be coiled may be supplied to the guide 63 from a reel I disposed above the guide and carried by a bracket II fixed to the base II (Fig.

In the operation of the disclosed embodiment of my pre-coiling machine, the straight metallic ribbon 5| is led down through the ribbon guide 63 and into the space between the marginal end faces 42 and 46 of the discs 4| and 44. The ribbon enters this space just above the pinch point,

as shown in Fig. 5, and the guide 63 is so disposed that substantially half the width of the ribbon passes into this space, the other half entering the peripheral slot 6| between the guide discs 59 and 60. The discs 4| and 44 are rotated in unison in the direction of the arrow in Fig. 5, and the ribbon 5| is pinched between the disc faces 42 and 46 and bent edgewise around the outer edge 50 of the pilot ring 49. The ribbon 5| is firmly pressed against the ring edge 50 by the shoulder 16 forming the bottom of the guide disc slot 6|. As the ribbon is bent to circular helical form, its inner edge portion is bent or offset laterally by engagement between the beveled pilot ring edge and the parallel beveled inner edge 43 of the inner disc face 42. The angle to which the inner edge portion of the ribbon is bent is less than 90 and preferably about 45 from its original position.

After passing the pinch point where it is bent, the ribbon is released by the separation of the disc faces 42 and 46. The radius of curvature of the inner edge of the ribbon approximates but slightly exceeds that of the outer edge 50 of the pilot ring 49 about which it is bent. As explained ISO SLQHCH ROOM above, the pilot ring runs eccentrically with respect to the outer disc 44, and the bent ribbon I5 accordingly also runs eccentrically until its inner edge passes outward beyond the periphery of the disc 44 at or near a point diametrically opposite the pinch point. The takeoff finger I2 leads the coiled ribbon l5 outward over the edge of the disc 44, and the helically coiled ribbon or fin thus progresses axially out of the mechanism.

In order to complete the process of forming an L-shaped foot along the inner edge of the ribbon, the pre-coiled ribbon is then subjected to the action of a beading machine which will now be described. This machine is claimed in my co-pending application Serial No. 734,961, filed March 15, 1947. The disclosed embodiment of my improved beading machine comprises generally two pairs of cooperating rollers 80, 8|, 82 and 83 having conical surfaces between which the pre-coiled ribbon 15 progresses, together with two foot forming rollers 84 and 85 which respectively engage and shape the edge portion of the ribbon in cooperation with the conical surfaced rollers.

As shown in Figs. 7, 8 and 9, a vertically extending frame plate 86 is mounted on a horizontal base 8'! and carries a journal bracket 88 in which a drive shaft 89 is journaled. The shaft 89 may be driven by any suitable means through a pulley 90, and carries a beveled pinion 9| at its inner end. Two angularly disposed shafts 92 and 93 are journaled in brackets 94 and 95 secured to one side of the frame plate 88 as shown in Fig. I. The shafts 92 and 93 are convergent, the upper shaft 92 slanting downward and inward toward the plane of the plate 86 and the lower shaft 93 slanting upward and inward so that the continuations of the axes of these shafts would intersect at or approximately at the center of rotation of the pre-coiled ribbon I5 passing through the machine. The shafts 92 and 93 are driven in the same direction by beveled gears 96 and 91 respectively fixed to the outer ends of the shaft and meshing with the beveled pinion 9|.

Two shafts I00 and IN are journaled in brackets I02 and I03 secured to the opposite side of the frame plate 86 from the shafts 92 and 93 (Fig. 8). The shafts |00 and |0I converge as do the shafts 92 and 93, the projected axes of all of these shafts intersecting at or substantially at the center of the axis of rotation of the precoiled ribbon 15. Intermeshing beveled gears I04 and I05 are respectively secured to the shafts 92 and I00 adjacent the inner edge of the plate 86, and similar intermeshing gears I06 and I0! are respectively fixed to the shafts 93 and IN. With this arrangement, the shafts I00 and IOI are both driven in the same direction which is opposite to the direction of rotation of the shafts 92 and 93.

The inner ends of the shafts 92 and 93 carry frusto-conical ribbon gripping rollers 80 and 82 of identical design, and similar rollers 8| and 83 are similarly fixed to the inner ends of the respective shafts I00 and II. The rollers 80 and 8| are illustrated in enlarged section in Fig. 10, and since the rollers 82 and 83 are respectively identical with the rollers 80 and 8| they will not be separately described. As shown in Fig. 10, the conical slope of the roller faces is such that projections of elements of these faces pass through the point where the projected axes of the shafts 92 and I00 intersect substantially at the axis of rotation of the coiled fin ribbon 15. The roller 80 has a bead I08 forming a shoulder adjacent its larger end, and carries a forming plate I09 fixed to its smaller end by a stud H and a nut I I I. The marginal portion of the end face of the plate I08 has formed therein a circular recess forming a surface H2 disposed at right angles to elements of the conical surface of the roller. The roller 8| carries a forming plate H3 fixed to its smaller end by a stud H4 and a nut H5. The peripheral surfaces of the plates II 3 and I08 are shaped to be aligned with and to form continuations of the conical surfaces of the respective rollers 8| and 80. The end face of the forming plate H3 is dished so as to present a marginal portion disposed at right angles to the conical surface of the roller 8|. The rollers 80 and 8| .are so disposed that their conical surfaces are parallel and are spaced apart a distance substantially equal to the thickness of the fin ribbon I5, the arrangement being such that the fin is tightly gripped and advanced by these rollers when they rotate. The periphery of the forming plate H3 on the roller 8| extends beyond the surface I I2 in the recess of the plate I09 on the roller 80 by a distance substantially equal to the thick ness of the fin metal.

A cylindrical roller 84 a pivot H1 with its axis substantially horizontal and at right angles to elements of the conical roller surfaces and its periphery engaging the marginal end face of the forming plate H3 and extending over the surface H2 of the forming plate I09. The roller pivot I I! is carried by a frame plate H8 fixed to the base 8'! and by a bracket H9 fixed to the plate H8 and having a roller receiving recess in its end as shown in Fig. 10. A cylindrical roller 85, identical with the roller 84 is pivotally mounted to bear against the ends of the conical rollers 82 and 83 in the same manner as that described above in connection with the roller 84. A peripherally slotted guide roller I is rotatably journaled in a bracket I2I fixed to the plate 88 and is disposed above and substantially in vertical alignment with the space between the rollers 80 and 8I. A similar peripherally slotted guide roller I22 is rotatably mounted in a bracket I23 below and substantially aligned with the space between the lower conical rollers 82 and 83.

Suitable means may be provided for guiding the precoiled ribbon or fin I5 to the beading mechanism and for leading the finished fin away from that mechanism after the forming operation performed therein is completed. As illustrated in Fig. 9, the pre-coiled fin delivery guide may comprise a drum I25 rotatably mounted on a shaft I26 supported by a bracket I21, fixed to the base 81. The drum is of slightly smaller diameter than the internal diameter of the precoiled fin I5, and may be of any desired length. The mechanism for receiving the finished coiled fin may comprise a similar drum I28 rotatably carried by a shaft I28 supported in a bracket I30 fixed to the base 81. The drums I25 and I28 may be of the same diameter and are of such size that the coiled ribbon readily clears these surfaces and slips on and off the drums Without binding. The drums I25 and I28 are each disposed at a small angle to the axis of the fin turn passing between the beading machine rollers, so that adjacent turns are held out of contact with the parts of the machine, as shown in Fig. 9.

In the operation of the beading machine in completing the method of the invention, a section of the ribbon I5 that has been pre-coiled in the bending machine and carries the angularly bent inner edge portion I3I is placed on the guidis rotatably supported on ing drum I25 and its leading end is started downward through the peripheral slot of the guide roller I20 and between the rollers and 8|. The four conical rollers 80, BI, 82 and 83 are rotated in the directions indicated by the arrows in Figs. 7 and 8, and the ribbon I5 is successively drawn between the conical surfaces of the cooperating pairs of rollers 80, 8 I, 82 and 83. The ribbon is tightly gripped by these rollers and as it passes between the first pair 80 and 8I, the periphery of the cylindrical roller 84 bends the inner edge of the ribbon down against the end surface H2 carried by the roller 80 so that an L-shaped foot I32 lying at right angles to the body of the fin ribbon is formed. This bending action is illustrated in Figs. 7 and 10. The second pair of conical rollers 82 and 83 and a cooperating cylindrical roller 85 complete the bending operation and hold the foot and ribbon in proper bent relation. If desired, the clearance between the lower cylindrical roller 85 and the cooperating end faces on the conical rollers 82 and 83 may be less than that between the corresponding parts of the upper rollers 80, 8I and 84, so that the bending of the foot I32 to final form is accomplished in two steps. Where the composition of the fin metal or the dimensions of the fin ribbon permit, one of the sets of foot forming rollers may be omitted. During the bending operation, the shoulders formed by the beads I08 at the larger ends of the rollers 80 and 82 engage the outer edge of the fin ribbon and so limit its movement outwardly parallel to the conical roller surfaces. This insures a uniformly bent foot I32 of the desired dimensions. The ribbon is guided below the bending rollers by the guide roller I22.

The forming surfaces of the pre-coiling and ribbon beading machines are preferably formed of hardened and ground steel of high strength and quality. These surfaces include the marinal end faces 42 and 45 of the discs 4| and 44 as well as the pilot ring 48 in the pre-coiling machine, and the forming plates I08 and H3 and rollers 84 and 85 in the beading machine.

I claim:

1. In a method of forming a pre-coiled helical fin for cylindrical elements, the steps which consists of continuously bending a fiat straight metallic ribbon edgewise around and in contact with a circular beveled curved surface to form a helical coil, and simultaneously'bending the inner edge portion of the strip by contact with said bevelled curved surface at an angle less than a right angle to the remainder of the strip.

2. A method of forming a plgggilg d helical fin for engine cylinders and the like comprising continuously bending a flat straight metallic ribbon edgewise around and in contact with a curved surface to form a helical coil and simultaneously bending the inner edge portion of the strip at an angle less than a right angle to the body of the strip, and then continuously further bending the bent inner edge portion of the coiled strip until it is disposed normal to the body of the strip to form a continuous L-shaped foot portion along the inner edge of the coiled strip for engagement with a cylindrical surface surrounded by the fin.

3. A method of forming a pre-coiled helical fin for engine cylinders and the like comprising continuously bending a fiat straight metallic ribbon edgewise around and in contact with a circular beveled surface to form a helical coil with the inner edge portion of the strip bent at an 75 angle less than a right angle to the body of the 0mm? HUUW strip, and then continuously further bending the UNITED STATES PATENTS bent inner edge portion of the coiled strip while confining the remainder of the strip against Number Name Date 1,032,925 Miller July 16, 1912 bending movement until said edge portmn is dis- 1,623,766 Way Apr. 5, 1927 posed normal to the body of the strip to form a. 5 1 668 534 Berg May 1 1928 continuous L-shaped foot portion along the inner 1,818.18) Weston Aug 11, 1931 edge of the coiled strip for engagement with a cylindrical surface surrounded by the fin. 2372795 Rodeck 1945 ERNEST BRUEGGER.

REFERENCES CITED The following references are of record in the file of this patent: 

